Amyloid protein may have been passed on through brain surgery

A study published by UK researchers suggests that the hallmark Alzheimer’s protein, amyloid, may have been passed to a small number of people during childhood brain surgery.

The authors suggest that amyloid could be acting in a similar way to the prion protein responsible for Creutzfeldt-Jakob disease (CJD). The findings are reported this Thursday 15 February, in the journal Acta Neuropathologica.

There is evidence that amyloid protein may spread within a person’s brain in a similar manner to the prion protein. Prion proteins can be passed between people through surgical equipment but this sort of transmission hasn’t been recorded for amyloid.

Previous research in animals has shown that directly introducing certain forms of the amyloid protein into an otherwise healthy brain can trigger disease processes. In 2015 evidence emerged suggesting that amyloid may have passed between people by way of a now discontinued medical procedure involving the transfer of growth hormones.

In this study researchers reviewed brain tissue held in an archive at the National Hospital for Neurology and Neurosurgery at University College London to identify younger people with cerebral amyloid angiopathy (CAA). CAA involves amyloid protein building up in the brain’s blood vessels and can lead to stroke and an increased risk of developing dementia. The risk of CAA increases in old age but is very rare in younger people.

The search revealed four cases of CAA in younger people, three in their thirties, and one in their fifties, who didn’t have any of the genetic risk factors for excessive amounts of amyloid build-up. The researchers found that all four of these people had received some form of childhood brain surgery.

Researchers then searched the medical literature and discovered a further four cases in which people who underwent childhood brain surgery went on to develop CAA before the age of 55.

Dr David Reynolds, Chief Scientific Officer at Alzheimer’s Research UK, said:

“While it is too early to draw any firm conclusions from such a small study, the finding that people with a rare amyloid-related disease all had brain operations early in life raises the possibility of amyloid having been passed from one person to another during neurosurgery.”

“Any potential link will need to be explored in much larger studies, but it is important to remember that people receive vital and often life-saving brain surgery every day in the UK and any potential risk of disease from these procedures is minimal. Since the surgeries relating to these findings were carried out, strict guidelines surrounding the sterilisation and use of equipment during surgery have been introduced and continue to be evaluated.”

“This study didn’t look at whether those who underwent neurosurgery in childhood went on to develop Alzheimer’s disease and there is currently no evidence that Alzheimer’s can be transmitted through brain surgery.”